Prosthetic Heart Valves

ABSTRACT

A prosthetic heart valve (e.g., a prosthetic aortic valve) is designed to be somewhat circumferentially collapsible and then re-expandable. The collapsed condition may be used for less invasive delivery of the valve into a patient. When the valve reaches the implant site in the patient, it re-expands to normal operating size, and also to engage surrounding tissue of the patient. The valve includes a stent portion and a ring portion that is substantially concentric with the stent portion but downstream from the stent portion in the direction of blood flow through the implanted valve. When the valve is implanted, the stent portion engages the patient&#39;s tissue at or near the native valve annulus, while the ring portion engages tissue downstream from the native valve site (e.g., the aorta).

The present application is a continuation of U.S. patent applicationSer. No. 17/550,339, filed Dec. 14, 2021, which is a continuation ofU.S. Pat. No. 11,229,516, filed on May 20, 2019, which is a divisionalof U.S. patent application Ser. No. 14/541,944, filed Nov. 14, 2014,which is a continuation of U.S. Pat. No. 9,572,660, filed Nov. 24, 2009,which is a National Phase of PCT Patent Application No.PCT/US2008/007015 filed on Jun. 4, 2008, which claims the benefit ofU.S. provisional patent application 60/933,274, filed Jun. 4, 2007, thedisclosures of which are hereby incorporated by reference herein.

BACKGROUND OF THE INVENTION

This invention relates to prosthetic heart valves. For the most part,the invention will be illustratively described in the context of aprosthetic aortic valve that can be temporarily collapsed during aportion of the implantation procedure, and that can be subsequentlyexpanded to its full size at the implantation site. The invention is notnecessarily limited to this particular type of use, however, and it willbe appreciated that various aspects of the invention can be used inother ways and/or in other contexts.

Many people with severe aortic stenosis go untreated because they arenot considered to be suitable candidates for aortic valve replacementusing the known prostheses and procedures (e.g., open-chest, open-heartsurgery). In an attempt to provide ways of treating these patients,collapsible prosthetic valves have been developed for insertion withinstenotic aortic valve leaflets in less invasive ways. For example, suchless invasive delivery of the prosthetic valve may be via catheter-like,trocar-like, or laparoscopic-type instrumentation. The delivery may bepercutaneous (e.g., via vessels of the patient's circulatory system thatlead to the aortic valve), or it may be through the wall of the heart(e.g., through the apex of the left ventricle of the heart (i.e.,transapically)), etc. It is believed, however, that current designs forprosthetic valves that are to be delivered in ways such as these are inneed of improvement with respect to aspects such as (1) long-termdurability, (2) the possibility of undesirable impingement on theadjacent mitral valve, (3) paravalvular leakage, etc.

BRIEF SUMMARY OF THE INVENTION

A prosthetic heart valve in accordance with the invention may include anannular supporting structure that has (1) an annular stent portion and(2) a ring portion that is substantially concentric with the stentportion but that is downstream from the stent portion in the directionof blood flow through the valve when the valve is in use in a patient.The stent portion has a blood-outflow region that includes a pluralityof annularly spaced commissure tips at which the stent portion isclosest to the ring portion. The ring portion is connected to the stentportion substantially solely by flexible strut structures that extendfrom the stent portion to the ring portion adjacent to the commissuretips. Each of the strut structures starts from a respective point orpoints on the stent structure that are farther from the ring portionthan the commissure tips. The valve further includes a plurality ofvalve leaflets supported by the stent portion. The ring portion isdownstream from the stent portion sufficiently far that the leafletscannot contact the ring portion.

The supporting structure is preferably annularly compressible andre-expandable. The stent portion is preferably adapted to engage tissueof the patient at or near the native heart valve annulus of the patient.(This engagement may be through other material that has been used tocover the stent portion.) The ring portion is adapted to engage theinside of a blood vessel of the patient downstream from the native heartvalve annulus. (Again, this engagement may be through other materialthat has been used to cover the ring portion.)

The ring portion may be integrally connected to the stent portion. Thering portion and the stent portion may be annularly compressible tosubstantially the same circumference. The ring portion may bere-expandable to a circumferential size that is greater than thecircumferential size of at least a part of the stent portion when thestent portion is re-expanded.

The stent portion may include a skirt portion that is adjacent to theblood inflow end of the valve when the valve is in use in a patient. Theskirt portion may re-expand to flare radially out from a remainder ofthe stent portion. The inflow end of the stent portion (e.g., the skirt)may be scalloped in an annular direction around the heart valve to avoidimpingement on another of the patient's heart valves or other structuresin the patient's heart.

The supporting structure may include barbs that engage tissue of thepatient when the valve is in use.

The ring portion may be constructed so that it is more resistant toannular compression than the stent portion.

The stent portion may include a blood-outflow-edge structure thatcomprises (1) a first ring member that extends annularly around thevalve in a serpentine pattern and that has a relatively large number ofconnections to other upstream structure of the stent portion, and (2) asecond ring member that (a) follows the first ring member annularlyaround the valve in a similar serpentine pattern, (b) is spaceddownstream from the first ring member, and (c) has a relatively smallnumber of connections to the first ring member. The ring portion may beattached to the stent portion by connections between the ring portionand the second ring member. The last-mentioned connections may connectto points on the second ring member that are closest to the ringportion. Portions of each of the leaflets may be inserted between thefirst and second ring members.

Sheet material (e.g., fabric and/or tissue) may be provided for coveringat least part of the stent portion and/or at least part of the ringportion. Any of this sheet material may be attached to the inside and/oroutside of the stent portion and/or the ring portion. Such sheetmaterial covering may comprise one layer or more than one layer.Different sheet materials may be used at different locations; and wheremultiple layers are used, different sheet materials may be used invarious combinations in different layers. If the valve includes theabove-mentioned first and second ring members, then sheet material (ofan above-mentioned type) may be provided for covering the first and/orsecond ring members. If leaflet portions are inserted between the firstand second ring members, then sheet material may be interposed betweenthe leaflets and the first and second ring members.

Further features of the invention, its nature and various advantages,will be more apparent from the accompanying drawings and the followingdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified elevational view of an illustrative embodiment ofa component of a prosthetic heart valve in accordance with theinvention.

FIG. 2 is a simplified isometric or perspective view of the FIG. 1component.

FIG. 3 shows the component of FIGS. 1 and 2 cut at one location aroundits perimeter and basically flattened out (although not all parts of thestructure are shown lying in one plane such as the plane of the paper onwhich FIG. 3 is drawn).

FIG. 4 is a simplified perspective or isometric view of what is shown inFIG. 3 .

FIG. 5 is a simplified, partial, elevational view of a component that isat least generally similar to what is shown in FIG. 1 .

FIG. 6 is similar to a lower portion of FIG. 5 , but with the fullannular structure shown, and with the addition of another component alsoshown.

FIG. 7 is similar to FIG. 6 , but with another additional componentshown.

FIG. 8 is again similar to FIG. 5 , but with the full annular structureand still more added components shown.

FIG. 9 is a simplified elevational view of an illustrative embodiment ofa complete prosthetic heart valve in accordance with the invention.

FIG. 10 shows a representative portion of a structure like that shown inseveral earlier FIGS., with certain parts emphasized with specialshading for purposes of further discussion.

FIG. 11 is a simplified depiction of what is shown in FIG. 10 from thedirection indicated by the arrows 11-11 in FIG. 10 .

FIG. 12 is similar to FIG. 3 , but for another illustrative embodimentin accordance with the invention and in another operating condition.

FIG. 13 is an enlargement of a portion of FIG. 12 .

FIG. 14 shows the FIG. 12 structure in the round and fully expanded.

FIG. 15 is similar to FIG. 12 for yet another illustrative embodiment ofthe invention.

FIG. 16 is similar to FIG. 14 , but for the FIG. 15 embodiment.

FIG. 17 is similar to FIG. 15 for still another illustrative embodimentof the invention.

FIG. 18 is similar to FIG. 16 , but for the FIG. 17 embodiment.

FIG. 19 is similar to FIG. 18 , but with some further components added.

FIG. 20 is similar to FIG. 17 for yet another illustrative embodiment ofthe invention.

FIG. 21 is similar to FIG. 20 for still another illustrative embodimentof the invention.

FIG. 22 is similar to FIG. 21 for yet another illustrative embodiment ofthe invention.

FIG. 23 is similar to FIG. 22 for still another illustrative embodimentof the invention.

FIG. 24 is a simplified isometric or perspective view showing the FIG.23 structure in its circumferentially expanded state or condition.

FIG. 25 is a simplified partial isometric or perspective view showinganother illustrative embodiment of the invention.

FIG. 26 is similar to FIG. 24 for yet another illustrative embodiment ofthe invention.

FIG. 27 is similar to FIG. 26 for still another illustrative embodimentof the invention.

FIG. 28 is a simplified view looking down on a lower part of thestructure shown in FIG. 25 .

FIG. 29 is a simplified view similar to FIG. 28 with an illustrativeembodiment of possible further components added in accordance with theinvention.

FIG. 30 is a simplified view similar to FIG. 29 with an illustrativeembodiment of still more components added in accordance with theinvention.

FIG. 31 is a simplified elevational view of an illustrative embodimentof a component that can be used in valves in accordance with theinvention.

FIG. 32 is a simplified side view (flattened out to a plane) of anillustrative embodiment of a representative portion of what is shown inFIG. 30 in accordance with the invention.

FIG. 33 is similar to FIG. 29 for another illustrative embodiment inaccordance with the invention.

FIG. 34 is again similar to FIG. 29 for yet another illustrativeembodiment in accordance with the invention.

FIG. 35 is similar to FIG. 31 for another illustrative embodiment inaccordance with the invention.

FIG. 36 is again similar to FIG. 29 for still another illustrativeembodiment in accordance with the invention.

DETAILED DESCRIPTION

This detailed description will begin with discussion of an illustrativeembodiment of a primary metal component 10 (initially with reference toFIGS. 1-4 ) that is included in valves in accordance with the invention.Other possible components of a complete valve may be mentioned in thisdiscussion of component 10, but more attention will be given to suchpossible other components later in this specification. The valves ofthis invention are collapsible and expandable in the circumferentialdirection. FIGS. 1-4 and other early FIGS. show illustrative embodimentsof these valves (or portions or components of these valves) in theircircumferentially expanded condition configuration. Some of the laterFIGS. illustrate how valves of this type circumferentially collapse.Alternative terms that may be used for circumferential (in the contextof collapse and re-expansion of a valve) include annular (in the senseof ring-like (especially like a closed ring)), diametrical, radial, andthe like.

The valves of this invention can be used in patients who need an aorticvalve replacement, but who may not be treated adequately by currentlyavailable prostheses and/or procedures. Valves in accordance with thisinvention can be implanted percutaneously, transapically, or surgically,with or without resected and/or debrided native leaflets. Metalcomponent 10 can be cut from a highly elastic and/or shape-memory alloy(e.g., nitinol) so that it is self-expanding, or from another metal(e.g., stainless steel, cobalt-chromium, platinum-iridium, etc.) thatnecessitates balloon expansion after annular reduction. A way that metalcomponent 10 can be made is by using a laser to cut it from startingstock that is a metal tube. Alternatively, metal component 10 can belaser-cut from a flat metal sheet and then rolled into a hollow annulusin which the formerly free ends or side edges of the flat material arejoined together by any suitable means such as welding.

Component 10 may have any or all of the features that are described inthe following paragraphs.

Illustrative component 10 includes a collapsible and expandable “upper”ring portion 100, and a collapsible and expandable “lower” stent portion200 (which is also a ring). (The words “upper” and “lower” are used onlyas convenient, relative terms, and without any intention to limit whatis referenced to any particular orientation relative to some absolutereference direction). In general, the stent portion 200 surrounds theleaflets of the prosthetic valve. The blood inflow end or edge of thevalve is at or adjacent the lower end or edge of stent portion 200 asviewed in FIG. 1 . The blood outflow end or edge of the valve is at oradjacent the upper end of stent portion 200 as viewed in FIG. 1 . Ringportion 100 is downstream from stent portion 200 in terms of thedirection of blood flow through the valve. Moreover, the annularstructure of ring portion 100 is preferably downstream from the reach ofany portion of the leaflets of the valve in any operating position ofthese leaflets so that no portion of the leaflets can ever contact anysignificant portion of at least the annular structure of ring portion100. Indeed, when the valve is in use in a patient, ring portion 100 istypically disposed in the patient's aorta downstream from the valsalvasinus.

Ring portion 100 and stent portion 200 both include a number of cells(each of which has a closed perimeter surrounding an open center) thatare collapsible and expandable in a direction that is circumferentialaround component 10. Reference number 110 points to a typical such cellin ring portion 100, and reference number 210 points to a typical suchcell in stent portion 200. Making component 10 of such cells contributesto the ability of component 10 to shrink (collapse) and/or expand in thecircumferential direction. Ring portion 100 may have cells of differentsizes than the cells of stent portion 200 in order to facilitate ringportion 100 reaching a different, finally expanded diameter than stentportion 200. For example, it may be desirable for ring portion 100 toreach a final expanded diameter that is greater than the final expandeddiameter of stent portion 200. This may enable ring portion 100 tobetter fill and bear against the adjacent portion of a patient's aorta(e.g., at or near the sinotubular junction (where the aortic sinus bulgeends and the aorta begins)), while stent portion only has to fill andbear against the patient's diametrically smaller aortic valve annulus.Cells 110 in ring portion 100 that are larger than cells 210 in stentportion 200 may help ring portion 100 expand to the above-mentionedlarger final diameter.

Differential radial force may also be provided by ring portion 100 andstent portion 200. For example, it may be desirable for ring portion 100to provide more radial force (to the adjacent aorta wall) than stentportion 200 provides (to the native aortic valve annulus). Larger cells(like 110) with “heavier” metal sides in ring portion 100 (as comparedto stent portion 200) can contribute to causing ring portion 100 toapply more radially outward force than stent portion 200. A side of acell that is “heavier” has a larger cross section (more material) than acell side that is “lighter.” Thus it will be noted that the sides ofcell 110 are heavier (wider and/or thicker) than the sides of cell 210.

In general, the provision of ring portion 100 allows for greater overallstructural integrity of component 10 (and hence the valve as a whole),while distributing holding forces more evenly. For example, this canavoid the need for a high-radial-force stent, which could causeundesirable deformation of the patient's mitral valve (which is adjacentto the aortic valve). This better, more widely distributed holding forcecan also reduce the need to use the patient's native, possibly stenoticleaflets (if present) as the primary anchoring mechanism for theprosthetic valve.

Illustrative component 10 includes barbs 120 that are placed on thedistal (downstream) portion of the ring 100 that expands into the aorta.Barbs 120 (which point in the downstream direction) help preventmigration (especially downstream shifting) of the implanted valve. Othergenerally similar barbs can be employed at various other locations oncomponent 10 to help prevent valve migration. For example, barbs can beprovided that point upstream, downstream, clockwise, counter-clockwise,or in any other direction, and they can be provided on ring portion 100,stent portion 200, or both.

The lower (blood inflow edge) portion of stent portion 200 is designedto conform to the anatomy of the heart without impinging on thepatient's mitral valve. In particular it will be noted that adjacent oneof the three commissure posts or regions of component 10 (i.e., atreference 220 a) the inflow edge of component 10 is higher than it isadjacent the other two commissure posts or regions (i.e., at references220 b and 220 c). A valve including component 10 is preferably implantedso that higher inflow edge portion 220 a is adjacent to the patient'smitral valve. This helps prevent the prosthetic valve from impinging onthe mitral valve. This low profile of stent portion 200 means the areaadjacent to the mitral valve is designed to reduce the possibility ofchordal entanglement and mitral valve impingement. In general, thestent/valve is designed to reduce interference with various anatomicaland/or physiological constraints. Such constraints may include avoidanceof mitral valve impingement, avoidance of chordae entanglement,avoidance of interference with the heart's various electrical conductionsystem pathways, etc.

Dual open bars 130 are provided for connecting ring portion 100 to stentportion 200 in the vicinity of the tip of each commissure region ofstent portion 200. This allows for redundant support in a high stressarea, while also allowing some bending and/or twisting to conform to thepatient's anatomy.

Stent portion 200 includes an independent stent-in-stent design asindicated at references 230 a and 230 b. In particular, stent portion200 includes two congruent, serpentine, blood-outflow-edge-regionmembers 230 a and 230 b. Each of these members 230 is a ring thatextends annularly all the way around stent portion 200. Each of thesemembers 230 undulates alternately up and down as one proceeds in theannular direction around the valve so that each member is “high” nearthe tip of each of three commissure regions 236 of the valve, and “low”between each annularly adjacent pair of such commissure regions. (“High”means extending farther in the blood flow direction; “low” meansextending not as far in the blood flow direction. This undulation ofmembers 230 may also be referred to as a serpentine pattern.) Everywherein the annular direction around component 10 member 230 b is higher than(i.e., spaced downstream from) member 230 a. At several locations 232that are spaced from one another annularly around component 10connections or links are provided between members 230 a and 230 b.Elsewhere, however, members 230 a and 230 b are able to move relative toone another. Hence the description of this structure as an “independentstent-in-stent design.”

This independent stent-in-stent design facilitates good leafletcoaptation near the top of each commissure post 236, while helping tomaintain a flexible stent. This increased flexibility (which maycontrast with designs that use a straight vertical bar for eachcommissure post region) may reduce stress concentration on the leaflets(which may be tissue, for example). Reduced leaflet stress concentrationis conducive to longer valve life or durability. Amplifying what isbeing said about flexibility, making structure 230 a relativelyindependent of structure 230 b in the vicinity of stent posts 236 meansthat the stent posts (actually provided by structure 230 a and notstructure 230 b) can be made as flexible as is desired. The relativelyindependent valve anchoring structure (e.g., ring 100, the lower portionof stent 200, and the structures 130 and 230 b that link the two) can bemade stiffer (relatively less flexible) for completely secure anchoringof the valve in the implant site.

As shown in FIGS. 3 and 4 , a lower “skirt” portion 240 of stent 200and/or ring 100 can be deflected out of projections of the tubulargeometric figure in which the major portion of stent 200 lies. Inparticular, these deflections may be radially outward from theabove-mentioned tubular geometric figure projections. These radiallyoutwardly projecting portions of component 10 (along with some radiallyoutward force from the midsection of stent portion 200) help hold theimplanted valve in place in the patient with or without the patient'snative, stenotic leaflets to help hold it in place.

The smooth contours (in the annular direction) of the outflow edge 230a/230 b of stent portion 200 may facilitate the use of naturallycontoured leaflets. This may be unlike other designs that use a verticalbar for each commissure region. Additionally, this smooth outflow edgemay help reduce or eliminate stagnant blood flow zones, which mightotherwise arise where a leaflet abruptly changes direction at the bottomof a vertical bar. The above-mentioned smooth outflow edge contour isthe result of outflow edge members 230 a/230 b being smoothly serpentineor undulating in the annular direction around structure 10.

Although component 10 includes a ring 100 in the patient's aorta, thereare large openings 140 between stent portion 200 and ring portion 100 toallow for blood flow to freely pass to the coronary arteries. Theselarge openings 140 also reduce the chance of leaflet abrasion from thefree edge due to leaflet contact with other parts of the prostheticvalve structure.

As has been mentioned, different cell dimensions in different parts ofcomponent 10 allow for different amounts of expansion and forcegeneration in different parts of the device. Some of this cell structurecan be converted to other circumferentially expandable structure (e.g.,serpentine or undulating members extending generally in thecircumferential direction) to allow for different types of behavior(e.g., with respect to amount of expansion and/or amount of force thatcan be generated).

To further reduce or eliminate leaflet abrasion at the leafletattachment site, stent portion 200 can first be covered with fabric,followed by a thin layer of buffering tissue, and finally leaflettissue. Inventive aspects of this kind will be discussed in more detaillater in this specification.

The elongated slots 234 between the two blood-outflow-edge-regionmembers 230 a and 230 b allow for (1) a flexible stent (as discussedearlier in this specification), (2) uninterrupted suturing of othermaterials such as leaflets over structure 10 (as opposed to smallerstent holes hidden beneath those other materials), (3) easily polishededges, and (4) a reduction in stress concentration from point suturing.

Skirt portion 240 can be scalloped (e.g., higher and less radiallydeflected in area 220 a than elsewhere around structure 10). This canallow skirt 240 to conform more readily to the natural contours of thepatient's aortic annulus, which may improve the placement and holdingforce of the prosthetic valve, as well as helping to reduce or eliminateparavalvular leakage.

Bends in certain areas like 150 a, 150 b, 150 c, and 250 can result incomponent 10 having different diameters at different points along itslength. (“Length” refers to distance or location along the axis of bloodflow through the device. A “bend” is typically a deflection about ageometric circumference of the device. FIG. 4 shows what will be theinner surface of component 10 in a finished valve. The outer surface ofcomponent 10 is not visible in FIG. 4 .) Again, different diameters ofcomponent 10 at different locations along the length of that componentallow the valve to better conform to adjacent structures in thepatient's anatomy (e.g., the aorta toward the upper end of component 10,or the sub-annular geometry toward the lower end of component 10).

By conforming to the portion of the heart below the aortic valve, theholding force and paravalvular seal is improved.

The upper portion of the stent-in-stent design (e.g., in areas likethose referenced 236 and 130) can be contoured to the shape of thepatient's native aortic root. By this it is meant that these upperportions of the stent-in-stent design can gradually taper outward withthe aorta since the aorta is larger than the native valve annulus. Thiscan provide additional anchoring of the prosthetic valve to thepatient's anatomy.

Another possibility is to have this portion (e.g., upper serpentinemember 230 b) bend away (i.e., radially outwardly) from other adjacentportions of the valve) to more gradually slope to the aorta diameter.This can allow for this section to be completely out of the way of theleaflet tissue attachments or free edges.

Component 10 can be partially or completely covered in one or morelayers of material or combinations of materials (e.g., polyester,tissue, etc.). This layer or layers can allow for such things as bettertissue in-growth, abrasion protection, sealing, and protection frommetal leachables such as nickel from nitinol. Again, various aspects ofhow component 10 can be covered will be considered in more detail laterin this specification.

FIG. 5 shows a side view of an embodiment of component 10 in which theradial shaping is more fully developed and depicted in at least some ofthe various ways that are shown and described earlier in thisspecification. FIG. 5 shows only one side (approximately half) ofcomponent 10. The opposite side (i.e., the rear half) is omitted fromFIG. 5 for greater clarity. It will be noted that component 10 in FIG. 5has different diameters at different points along its length. (Diametersare horizontal in FIG. 5 . Length is vertical in FIG. 5 (parallel to theaxis of blood flow through a finished and implanted valve).) Diameterchanges in FIG. 5 tend to be relatively smooth. Even the rate ofdiameter change tends to be relatively smooth (not too abrupt at anypoint along the length of the device) throughout component 10 in FIG. 5. Note again the base skirt flare 240 and the expanded section 100 forthe aorta in FIG. 5 . As mentioned earlier, the base flare helps tosecure the valve in place, and also to direct blood flow and preventleakage around the outside of the valve (paravalvular leakage). Anotherpossible feature that is shown in FIG. 5 (and carried through into somesubsequent FIGS. like FIGS. 8 and 9 ) is contouring or curving of aorticring 100 radially inwardly at the tips (i.e., at both the lower(upstream) tips like 103 and the upper (downstream) tips like 105). Thiscan help reduce or avoid perforation and/or dissection of the aorta byring portion 100. The embodiment of component 10 that is shown in FIG. 5is used as the component 10 in the series of FIGS. that will bediscussed next.

FIG. 6 illustrates a possible first step in attachment of other materialto component 10. FIG. 6 and subsequent FIGS. tend to show the addedmaterial as though it were transparent (which, in fact, it typically isnot). Thus these FIGS. tend to show the added material, for the mostpart, by means of a line at the visible limits of the material. Inaddition, some of these FIGS. show only the material being added in thestep that is the subject of that FIG. Such a FIG. tends to omitdepiction of material that was added in an earlier step or steps. Theearlier-added material is still present, but it is not specificallydepicted so that the FIG. that omits its depiction can focus on thematerial currently being added.

Continuing specifically with FIG. 6 (which shows only stent portion 200and omits depiction of ring portion 100), this FIG. shows covering allof stent portion 200 below member 230 b with a layer of material 300such as fabric. This covering may be both inside and outside the coveredportion of component 10. Among the possible purposes of material 300 maybe (1) promotion of tissue in-growth, (2) blood flow/sealing, and (3) toprovide an attachment base for subsequent layers of material. Allmaterial (i.e., 300 and subsequent material(s)) can be attached tocomponent 10 by means of suturing around component 10 struts and/orthrough dedicated eyelets and slots (not shown) in component 10. The “X”marks in FIG. 5 indicate some possible locations for such sutures.Examples of fabrics that are suitable for material 300 include Dacron,polyester, and Teflon.

FIG. 7 shows the addition of more material 400 over a portion ofmaterial 300. (Again, as explained earlier, FIG. 7 omits depiction ofmaterial 300 (which is still present on component 10) so that allattention can now be given to material 400. FIG. 7 also omits depictionof upper ring portion 100.) In particular, material 400 is applied overthe upper portion of material 300, both inside and outside the structurebeing built up. Material 400 may be a lubricious covering such as tissue(e.g., pericardium from any of several species, submucosa, and/orperitoneum) or polymer for sealing, reduced leachables, and a bufferbetween the stent and the moving leaflets. Again, the “X” marks, and nowalso the spiral marks, indicate some examples of where material 400 maybe sutured to the underlying structure.

FIG. 8 illustrates addition of final material and leaflets to thestructure being built up as described in the preceding paragraphs. Asheet of leaflet material 500 is added between each annularly adjacentpair of commissure regions. The U-shaped “lower” edge of each such sheetof leaflet material can be passed through the slots 234 between members230 a and 230 b and sutured to the underlying structure. The “upper”edge of each such leaflet sheet is the “free” edge of that leaflet. Eachleaflet sheet is shaped and includes sufficient material between thecommissure regions to which it is attached as described above so thatthe free edges of the three leaflets can come together in the interiorof the valve and thereby close the valve to prevent reverse blood flowthrough the valve when it is implanted and in use in a patient.

Typically after leaflets 500 have been added to the structure beingbuilt up, a lubricious covering 600 (e.g., porcine pericardium orpolymer) may be added over member 230 b. Covering 600 may also cover thelower portions of struts 130. (FIG. 8 shows covering 600 on theforeground portions of the valve, but omits depiction of it toward therear to avoid over-complicating the drawing.) Covering 600 preventsleachables and reduces any leaflet abrasion.

In addition to elements 500 and 600, FIG. 8 shows that material 700(e.g., a fabric such as Dacron, polyester, or Teflon) may or may not beprovided to surround the section of component 10 that will be in contactwith the aorta when the valve is in use in a patient. If provided, suchmaterial 700 can reduce leaching of metal and can help to secure thevalve in place via tissue in-growth. Note that if barbs 120 are presenton structure 10, they may remain uncovered for embedding into thepatient's tissue.

FIG. 9 shows another illustrative embodiment of a finished valve. Theonly significant difference from FIG. 8 is that in FIG. 9 material 700′covers the barbs 120 at the top of the valve. Note that the closesuturing of the various material layers to the underlying structureleaves the perimeter limits or contours defined by component 10 assubstantially the same perimeter limits or contours of the finishedvalve. As just one example of this, the scalloping of the lower portionof component 10 (e.g., at 220 a), which is provided to avoid impingingon the patient's mitral valve, remains a feature of the finished valve.

By way of recapitulation and further amplification of the above, somerefinement of the terminology used in the foregoing may be helpful tobetter distinguish the present invention from previously knownstructures. FIG. 10 shows again a portion of the primary metal component10 that has been shown in some of the earlier FIGS. A portion of FIG. 10has been shaded to emphasize the location of a flexible strut structure280 that connects ring portion 100 to stent portion 200. Strut structure280 is one of three similar strut structures that are spaced from oneanother annularly around component 10. Each strut structure 280 islocated adjacent a respective one of the three commissure regions 236 ofthe valve. Ring portion 100 and stent portion 200 are connected to oneanother substantially only by strut structures 280. Because each ofthese strut structures is adjacent a respective one of commissureregions 236, and because there is no other connecting structure betweenring portion 100 and stent portion 200, component 10 defines arelatively large and unobstructed opening 140 between each annularlyadjacent pair of commissure regions 236. This helps a valve of thisinvention avoid occluding the ostia of the coronary arteries. Theseostia can connect to the aorta where component 10 provides large andunobstructed openings 140.

In the illustrative embodiment shown in FIG. 10 , representative strutstructure 280 (shaded for emphasis) effectively begins (toward thebottom) where member 230 b is last connected to the remainder of stentportion 200 in the blood flow direction. This is at the uppermost links232 that are shown in FIG. 10 . Strut structure 280 then includes theportion of member 230 b that is above these uppermost links 232. Strutstructure 280 also includes dual open bars 130. At its upper end strutstructure 280 ends where bars 130 merge into the annular structure ofring portion 100.

From the foregoing it will be seen that strut structure 280 connects tothe remainder of stent portion 200 only well below the upper, free-endtips of the associated commissure region 236. (In FIG. 10 the arrow fromreference number 236 points to the tip of that commissure region.) Inother words, the uppermost points of attachment 232 of strut structure280 to the remainder of stent portion 200 are at a significant distancebelow the tip of the associated commissure region 236. For example, ifthe distance from the lowest to the highest point along the undulationof member 230 a around component 10 is H1 (see FIG. 1 ), and if thedistance from the highest link 232 (between members 230 b and 230 a) tothe tip 236 of the adjacent commissure region is H2 (see FIG. 10 ), thenH2 is preferably about 50% or an even larger percentage of H1. Stillmore preferably, H2 is about 75% or an even larger percentage of H1.(FIGS. 1 and 10 are not, of course, drawn on the same scale.) In otherwords, strut structure 280 extends down along at least about 50% (morepreferably at least about 75%) of the height of the associatedcommissure “post” portion of component 10 to its points 232 ofattachment to the remainder of stent portion 200. In the annulardirection this downwardly extending portion of strut structure 280preferably closely follows the associated commissure post (actuallyprovided by member 230 a) to avoid encroaching significantly on thedesirable large open spaces 140 between annularly adjacent commissureregions 236.

FIG. 11 is a view taken from the side of FIG. 10 as indicated by theline 11-11 in FIG. 10 . FIG. 11 again shows representative strutstructure 280 shaded for emphasis. FIG. 11 shows that strut structure280 can be deflected radially out from the tubular geometric shape inwhich the remainder of stent portion 200 tends to lie (in this extremelysimplified depiction). This radial outward deflection of strut structure280 can begin just above uppermost links 232, which (as has beenmentioned) can be quite low relative to where the tips 236 of thecommissure posts are. All of this can help keep strut structure 280 awayfrom contact with any moving portions of the valve leaflets (anchored,in the vicinity of what is shown in FIG. 11 , to member 230 a and not toany portion of structure 280) when the valve is in use in a patient. Itcan also facilitate making a gradual transition from the smallercircumferential size of the remainder of stent portion 200 to the largercircumferential size of ring portion 100. FIG. 11 illustrates therelative independence of strut structure 280 downstream from itsdownstream-most connection points 232 to the remainder of stent portion200. This independence of strut structures 280 and the adjacent portionsof the remainder of stent portion 200 (e.g., the adjacent portion ofmember 230 a) allows these features to be shaped, to deflect, and/or toflex independently of one another (e.g., in the radial direction).Leaflets 500 and other materials 300, 400, 600, and 700 are preferablyadded and attached in such a way as to not significantly interfere withthis independence of strut structures 280 and the adjacent parts of theremainder of stent portion 200. In other words, leaflet and othermaterials and their associated attachment sutures preferably do not spanbetween strut structures 280 and adjacent parts of stent portion 200 ina way that would tie these otherwise independent features together withundue relative-motion constraint. For example, in the vicinity of whatis shown in FIG. 11 , leaflet material preferably ends at member 230 a(extending only to the left from the portion of member 230 a that isshown in FIG. 11 ). Leaflet material preferably does not extendsignificantly to the right from member 230 a and is preferably notattached to structure 280 per se.

FIGS. 12-14 show the primary (tubular or hollow cylindrical) metalcomponent 1010 of another illustrative embodiment of a prosthetic heartvalve in accordance with this invention. Elements in FIGS. 12-14 thatare generally similar to previously described elements have referencenumbers in FIGS. 12-14 that are increased by 1000 from the referencenumbers previously used for the similar elements. FIG. 12 showscomponent 1010 cut axially along its length and then flattened (this isdone solely to simplify the depiction), but in the left-to-rightcondition that it has when it is annularly compressed or collapsed. FIG.13 shows an enlargement of the upper portion of FIG. 12 . FIG. 14 showscomponent 1010 in the round and in its fully expanded state.

In the embodiment shown in FIGS. 12-14 the leaflets of the valve can beattached to the angled posts 1260. In this embodiment the aorta portion1100 is made up, for the most part, of primary serpentine members 1160 aand 1160 b. Each of these members undulates in the axial direction(parallel to the axis of blood flow through the finished and implantedvalve) as one proceeds annularly around the valve. In addition,secondary serpentine members 1162 are used to connect members 1160 a and1160 b to one another. Secondary serpentine members 1162 undulate in theannular direction as they proceed generally axially between members 1160a and 1160 b. The use of serpentine members 1160 and 1162 in aortaportion 1100 allows for greater flexion and/or extension. For example,this can aid in the flexibility of component 1010 within a catheterbending along a tortuous path. It can allow for conformance to bendingwhen placed in the ascending aorta where it begins to arch. It can alsocompensate for pulsatile expansion/contraction of the aorta. Stressrelieving features 1164 aid in flexibility and reduction in stress.

As a general matter, embodiments like those shown in FIGS. 12-14 and insubsequent FIGS. may be capable of collapsing to a smallercircumferential size than embodiments like those shown in FIGS. 1-11 .Thus, for example, any of the embodiments shown herein may be suitablefor delivery (in a collapsed condition) into the patient through a smallincision and, e.g., through the apex of the heart. Embodiments likethose shown in FIGS. 12-14 and subsequent FIGS. may be additionallysuitable for delivery in other ways requiring collapse of the valve toan even smaller circumferential size. An example of such other deliveryis through the femoral artery.

FIGS. 15 and 16 show the primary (tubular or hollow cylindrical) metalcomponent 2010 of yet another illustrative embodiment of a prostheticheart valve in accordance with the invention. Elements in FIGS. 15 and16 that are generally similar to previously described elements havereference numbers in FIGS. 15 and 16 that are increased by 1000 or 2000from the reference numbers previously used for the similar elements. Tosimplify the depiction, FIG. 15 shows component 2010 cut axially alongits length and then flattened, but otherwise in the condition that ithas when it is annularly compressed or collapsed. FIG. 16 showscomponent 2010 in the round and in its fully expanded state. Like theembodiment shown in FIGS. 12-14 , the FIGS. 15-16 design allows forleaflet attachment to angled posts 2260, but the FIGS. 15-16 design alsohas a set of apertures 2262 to aid in suturing (e.g., for attachment ofthe leaflets.) Although shown as round or eyelet-shaped in FIGS. 15 and16 , apertures 2262 (or similar apertures in any other embodiment) canhave any other shape, if desired. Slots are just one example of suchother possible shapes for these apertures.

FIGS. 17-19 show the primary (tubular or hollow cylindrical) metalcomponent 3010 of still another illustrative embodiment of a prostheticheart valve in accordance with the invention. Elements in FIGS. 17-19that are generally similar to previously described elements havereference numbers in FIGS. 17-19 that are increased by 1000, 2000, or3000 from the reference numbers previously used for the similarelements. Again, to simplify the depiction, FIG. 17 shows component 3010cut axially along its length and then flattened, but otherwise in thecondition that it has when it is annularly compressed or collapsed. FIG.18 shows component 3010 in the round and in its fully expanded state.FIG. 19 shows component 3010 with cuff fabric 2170 and polymer leaflets2172 attached to the bottom sections, but with other possible materiallayers not shown. The design of FIGS. 17-19 allows for leafletattachment to a single, solid, independent post 3264 in each commissureregion, and with apertures 3266 for suture attachment.

FIG. 20 shows the primary (tubular or hollow cylindrical) metalcomponent 4010 of yet another illustrative embodiment of a prostheticheart valve in accordance with the invention. Elements in FIG. 20 thatare generally similar to previously described elements have referencenumbers in FIG. 20 that are increased by 1000, 2000, 3000, or 4000 fromthe reference numbers previously used for the similar elements. Again,to simplify the depiction, FIG. 20 shows component 4010 cut axiallyalong its length and then flattened, but otherwise in the condition thatit has when it is annularly compressed or collapsed. The serpentineshape 4282 of the support struts or linking members 4280 allows forgreater flexure and/or extension of the structure between ring portion4100 and stent portion 4200. This aids in the flexibility of component4010 within a catheter bending along a tortuous path. It also allows forconformance to bending when this portion of the implanted valve isplaced in the ascending aorta where it begins to arch. It also helps toaccommodate pulsatile expansion/contraction of the aorta. Shapes 4282are serpentine by virtue of undulation in directions that are annular ofthe valve as one proceeds along those shapes in the axial direction(i.e., from element 4100 to element 4200 or vice versa, which could alsobe described as parallel to the axis of blood flow through the finishedand implanted valve).

FIG. 21 shows the primary (tubular or hollow cylindrical) metalcomponent 5010 of still another illustrative embodiment of a prostheticheart valve in accordance with the invention. FIG. 21 is the samegeneral kind of drawing as FIG. 20 . Again, reference numbers areincreased by multiples of 1000 for generally similar features fromearlier-described embodiments. FIG. 21 illustrates the point that ringportion 5100 may be connected to stent portion 5200 by more than twostrut members 5130 adjacent each commissure post 5264. In particular, inthis embodiment there are four side-by-side struts 5130 adjacent eachcommissure post 5264. FIG. 21 also shows an example of a structure inwhich H2 is about 50% of H1 (generally analogous to the parameters H1and H2 earlier in this specification). In this type of embodiment H1 isthe approximate overall height of a solid commissure post 5264, and H2is the distance from the top of a commissure post 5264 to the highestconnection between the commissure post and a link 5130 to ring portion5100. FIG. 21 also shows other variations from earlier embodiments,which variations will be self-explanatory from what has already beensaid.

FIG. 22 is similar to FIG. 21 for yet another illustrative embodiment6010. In FIG. 22 there are six or eight links 6130 (depending on wherethe count is taken) between ring portion 6100 and stent portion 6200adjacent each of solid commissure posts 6264. Nevertheless, this designstill has large coronary openings 6140, as is the case for all of theother designs herein. FIG. 22 also illustrates a case in which H2 isapproximately 75% of H1, as those parameters are defined in thepreceding paragraph. FIG. 22 still further illustrates the provision ofeyelets 6175 on aortic ring portion 6100 and eyelets 6275 near the baseof each stent post that can be used for such purposes as material (like300, 700, and/or 8300 elsewhere in this specification) attachment and/orreleasable attachment of the valve to delivery apparatus.

FIG. 23 is similar to FIG. 22 for still another illustrative embodiment7010. In FIG. 23 there are again four links 7130 between ring portion7100 and stent portion 7200 adjacent each of solid commissure posts7264. FIG. 23 also illustrates another case in which H2 is nearly 75% ofH1, as those parameters are defined in earlier paragraphs.

FIG. 24 shows the structure from FIG. 23 in its circumferentiallyexpanded condition or state.

FIG. 25 shows the foreground portion of another illustrative embodiment8010 in its annularly or circumferentially expanded state or condition.Elements that are generally similar to elements from earlier embodimentshave reference numbers that differ by multiples of 1000 from thereference numbers used for those elements in earlier embodiments.Although FIG. 25 shows only the foreground portion of this structure, itwill be understood that this structure continues around behind what isshown in FIG. 25 to form a full, continuous, uninterrupted ringstructure, just as all of the other embodiments shown herein do. Thestructure that is visible in FIG. 25 is basically repeated two moretimes with equal angular spacing as one proceeds all the way around theclosed ring structure. As is true for all other embodiments throughoutthis specification, a prosthetic heart valve that includes structure8010 is circumferentially collapsible for less invasive delivery into apatient, and then re-expandable (e.g., to the size and shape shown inFIG. 24 ) when inside the patient at the prosthetic valve implant sitein the patient.

In the FIG. 25 embodiment, ring portion 8100 includes twocircumferentially extending rows of open-centered,collapsible/expandable cells. The cells in one of these rows havereference number 8110 a. The cells in the other row have referencenumber 8110 b. These two rows are partly overlapping in a directionalong a longitudinal axis through the valve (parallel to the directionof blood flow through the valve after it has been implanted and isfunctioning in a patient). Ring portion 8100 expands to a largercircumferential size than stent portion 8200 as shown in FIG. 25 .

Ring portion 8100 and stent portion 8200 are joined to one another bysix links or struts 8130 extending between those portions. (Only two ofstruts 8130 are visible in FIG. 25 .) Each pair of two such struts 8130is located close to a respective one of commissure posts 8264 on stentportion 8200. In particular, each strut 8130 in a given pair is locatedclose to a respective one of the two sides of the associated commissurepost 8264. As described for other embodiments earlier in thisspecification, this leaves relatively large open spaces 8140 in thecircumferential direction between adjacent pairs of the struts. Notethat struts 8130 flare radially outwardly as one proceeds along thestruts from the smaller-circumference stent portion 8200 to thelarger-circumference ring portion 8100.

Stent portion 8200 includes a single circumferentially extending row ofopen-centered, collapsible/expandable cells 8210. This row of cells 8210is interrupted by solid commissure posts 8264 at three equally spacedlocations around the circumference of stent portion 8200. Note that theconnections of each commissure post 8264 to the row of cells 8210 arequite low along the overall length of the commissure post. This giveseach commissure post 8264 a relatively long, upper, free end portion,along which the commissure post does not have any frame connection toany other portion of valve frame 8010. As in other embodimentsconsidered elsewhere in this specification, this gives most of thelength of each commissure post 8264 an independent flexingcharacteristic. By independent flexing it is meant that the flexingproperties of the post can be relatively independently of the flexingproperties of the rest of frame (especially the rest of stent portion8200). For example, each commissure post 8264 can be designed so thatits upper free end portion flexes radially inwardly and then radiallyoutwardly in response to each opening/closing cycle of the valveleaflets attached (in part) to that post. The amount of this flexing canbe designed into the relatively independent commissure posts relativelyindependently of the amount of stiffness that it is desired to give theother parts of stent portion 8200 (e.g., for such purposes as to enablethe stent portion as a whole to hold back native leaflet tissue, tosecurely anchor the prosthetic valve in the patient, etc.)

FIG. 25 shows apertures 8266 that can be provided in each commissurepost 8264 for the purpose of stitching (suturing) leaflets of theprosthetic valve (and possibly also other layers of tissue or material)to the commissure posts. In general, it is stated again that forembodiment 8010 (as for other embodiments described throughout thisspecification) flexible leaflets (like 500 in FIGS. 8 and 9 or like 2172in FIG. 19 ) can be attached to stent portion 8200 in the mannergenerally illustrated elsewhere in this specification. Similarly, it isagain stated that for embodiment 8010 (as for other embodimentsthroughout this specification) other layers of various materials can beattached to various other portions of frame structure 8010 (e.g., asshown at 300, 400, and 700 in FIGS. 6-9 and at 2170 in FIG. 19 ).

Still another feature that FIG. 25 illustrates is the scalloping of thelower end of stent portion 8200 so that this lower end or edge isrelatively high near the bottom of each commissure post 8264 (atreference number 8220) and lower at other locations in thecircumferential direction around the valve. This feature is also acharacteristic of other embodiments throughout this specification, andit can help the implanted prosthetic valve avoid interfering with otherstructures in the patient's heart (e.g., the patient's native mitralvalve when the prosthetic valve is implanted as a replacement aorticvalve).

FIG. 26 shows yet another illustrative embodiment 9010. Once again,elements that are generally similar to elements from earlier embodimentshave reference numbers that differ by multiples of 1000 from thereference numbers used for those elements in earlier embodiments. As forall other embodiments herein, a prosthetic valve that includes structure9010 is circumferentially collapsible for less invasive delivery into apatient, and it then re-expands (e.g., as shown in FIG. 26 ) when at theimplant site in the patient. As compared, for example, to FIG. 25 ,embodiment 9010 has a ring portion 9100 that includes only a singlecircumferential row of open-centered, collapsible/expandable cells 9110.The stent portion 9200 of embodiment 9010 also includes a singlecircumferential row of open-centered, collapsible/expandable cells 9210.However, some of these cells have some sides with extra folds or pleats,which can facilitate giving stent portion 9200 a different geometry,different stiffness in different locations, etc. Examples of such extrafolds or pleats are identified by reference numbers 9211 a and 9211 b.The struts or links 9130 in embodiment 9010 again have serpentineportions 9282 (like 4282 in FIG. 20 ).

FIG. 27 shows still another illustrative embodiment 10010. Thisembodiment has a stent portion 10200 that includes two circumferentiallyextending rows of open-centered, collapsible/expandable cells 10210 aand 10210 b. These two rows partly overlap in the axial direction (i.e.,in a direction along a longitudinal axis through the valve). Some ofthese cells have extra folds or pleats 10211 a, 10211 b (like 9211 a and9211 b in FIG. 26 ) for reasons similar to what is described above inconnection with FIG. 26 . The ring portion 10100 of structure 10010 is asingle serpentine ring (no open-centered, closed-perimeter cells as insome other embodiments). There are four struts 10130 adjacent each ofcommissure posts 10264 for connecting ring portion 10100 and stentportion 10200. FIG. 27 is therefore similar to FIGS. 21 and 23 in thisrespect. Between each group of four struts 10130, stent portion 10200includes some extra cells 10213 that extend toward ring portion 10100.These structures 10213 can help to hold back native leaflet tissue ofthe valve that is being replaced by the prosthetic valve and/or to helpanchor the prosthetic valve by hooking over the upper edge of theleaflets of the patient's native heart valve.

FIG. 28 and several subsequent FIGS. provide additional information asto how valves in accordance with this invention may be constructed. FIG.28 is a greatly simplified view looking down on the stent portion 8200of valve frame embodiment 8010 before any other elements have been addedto the valve frame. Embodiment 8010 is selected for use in FIG. 28 andsubsequent FIGS. solely as an example. Other frame embodiments shownelsewhere herein can be used instead if desired. FIG. 28 shows thatstent portion 8200 forms a closed ring, with commissure posts 8264 a-cspaced equally from one another around the ring and connected to oneanother by the inter-commissure row or rows of collapsible/expandablecells 8210. FIG. 28 shows this structure in its circumferentiallyexpanded condition. In embodiments of this general type, all of thecircumferential collapse and re-expansion of the valve is provided bycellular structure(s) like 8210 (or in some embodiments, serpentinestructure(s)). Commissure posts 8264 are “solid” and therefore notthemselves (individually) circumferentially collapsible orre-expandable.

FIG. 29 shows the addition of one or more layers of flexible, web-likeor sheet-like material annularly around the inside and/or outside ofstent portion 8200. For convenience herein, all of such sheet materialmay be referred to by the general reference number 8300. In theparticular example shown in FIG. 29 , sheet material on the outside ofstent portion 8200 has reference number 8300 a and sheet material on theinside of stent portion 8200 has reference number 8300 b. Sheet material8300 may be like any of earlier described material(s) 300, 400, 700,and/or 2170. See also FIG. 32 , which shows by dotted lines 8300 theupper and lower edges or limits of the sheet material on stent portion8200 (now shown flat and only in part). Sheet material 8300 may not needto be provided over both the inner and outer surfaces of stent portion8200, but that is one preferred arrangement. Sheet material 8300 may besecured to stent portion 8200 by sutures that pass through the sheetmaterial and also through and/or around various parts of stent portion8200. Among the important functions of sheet material 8300 are to helpthe valve seal the native valve annulus when the valve is implanted in apatient, and to help provide a seal between the prosthetic valveleaflets and the stent or annular portion of the valve.

Some examples of possible variations of what is described in theimmediately preceding paragraph are shown in FIGS. 33 and 34 . FIG. 33shows an illustrative embodiment with two layers of sheet material 8300b and 8300 c inside stent structure 8210/8264. In such an embodiment,inner-most layer 8300 c may be adapted for buffering and sealing of theflow of blood (especially in the pockets that are formed by leaflets 500in the interior of the valve). Thus, for example, inner-most layer 8300c may be made of tissue. Outer layer 8300 b may be adapted for sealingwith the patient's native anatomy and/or tissue in-growth from thatanatomy. Outer layer 8300 b may therefore be made of a fabric material.

FIG. 34 shows an illustrative embodiment with only one layer of sheetmaterial 8300 b inside stent structure 8210/8264.

FIG. 30 shows addition of three, flexible, prosthetic valve leaflets 500a c to the FIG. 29 structure. A representative one of these leaflets,prior to incorporation into the prosthetic valve, is shown by itself inFIG. 31 . As shown in FIG. 31 , each leaflet 500 may start as a flatsheet. The upper straight or relatively straight edge 510 of this sheetbecomes the free edge of the leaflet when the leaflet is assembled inthe prosthetic valve. Two approximately straight, upper, side edgeportions 520 a b of the leaflet can be attached, respectively, to two ofthe commissure posts 8264 of the prosthetic valve. The arcuate loweredge portion 530 of the leaflet can be attached (at least partly) tomaterial 8300 between the immediately above-mentioned two commissureposts 8264. All of reference numbers 510, 520, and 530 are shown in FIG.30 for a representative one of the leaflets, but to avoidover-complicating that FIG., only reference numbers 510 and 530 areshown for the two other leaflets.

FIG. 35 shows an alternative embodiment in which the lower edge 530 ofleaflet 500 arches up rather than down as in FIG. 31 . FIG. 36 showsanother alternative embodiment in which the lower edge 530 of leaflet500 is approximately straight across. The leaflet shape that is chosendepends on the operational characteristics it is desired to achieve. Forconvenience, the edge portion 530 that is generally opposite free edge510 may sometimes be referred to as the secured edge portion of theleaflet.

FIG. 30 shows the valve in the closed condition. The “free” upper edges510 of the three leaflets 500 a c come together in approximately a Yshape in the interior of the valve to provide a fluid seal between theleaflets. The side edges 520 a b and the lower edge 530 of each leafletare secured to the annular structure 8200/8300 of the valve in a waythat provides a seal between each leaflet and the adjacent portion ofthe annular structure. For example, this may be accomplished bystitching (suturing) edges 520 and 530 of each leaflet to the annularstructure as illustrated by FIG. 32 . In that FIG., “x” marks 540 areused to indicate where side edge portions 520 of a typical leaflet 500may be stitched (sutured) to cantilevered free end portions ofcommissure posts 8264 (e.g., through commissure post apertures 8266(FIG. 25 )). This stitching may additionally pass through material 8300.But even if there is material 8300 between a leaflet 500 and acommissure post 8264, the stitching 540 is preferably directly(straight) through the leaflet and through or to the commissure post sothat the stitching 540 can apply force from the leaflet directly to thecommissure post. Also in FIG. 32 , “o” marks 550 are used to indicatewhere the bottom edge of a typical leaflet 500 may be stitched at leastin part to the material 8300 that spans the open-cellular,inter-commissure structure 8210 of stent portion 8200 (betweencommissure posts 8264). The net result of all of this construction is toseal the entire side and lower perimeter 520/530 of each leaflet 500 tothe annular structure 8200/8300 of the valve, while leaving the upperedges 510 of the leaflets with sufficient slack to come together (asshown in FIG. 30 ) to close the valve (or to move apart to open thevalve).

The above-described continuous seal of leaflets 500 to the annularstructure (especially 8300) is effectively continued (by continuousannular web material 8300) to the native valve annulus by stent portion8200 pressing sheet material 8300 radially outwardly into annularsealing contact or engagement with the native valve annulus.

Continuous sheet material 8300 provides many more places 550 where thelower edges of leaflets 500 can be stitched to annular structure8200/8300 than would be provided by relatively widely spaced frameelements 8210 alone. This improves sealing between the leaflets and theannular structure. (Some of stitches 550 may also directly embrace(e.g., wrap around) elements of frame structure 8210. But others ofstitches 550 typically pass through only a leaflet 500 and sheetmaterial 8300.) Similarly, the continuous nature of sheet material 8300improves sealing between annular structure 8200/8300 and the patient'snative valve annulus. On the other hand, being able to secure(suture/stitch) the upper side edges 520 of each leaflet 500substantially directly to commissure posts 8264 (e.g., at locations 540)is desirable because these upper portions of the leaflet may tend to tryto pull away from annular structure 8200/8300 as the valve opens andcloses. Therefore, strong and relatively directleaflet-to-commissure-post attachment at points 540 is desirable toabsorb this cyclical tension at the ends of the upper free edge of eachleaflet. The cantilevered, upper, free end portions of commissure posts8264 can flex radially in and out in spring-like fashion to absorb theshock of this cycling leaflet tension and to reduce the maximumamplitude value that this tension reaches in its cycle. Because the freeend portions of commissure posts 8264 are cantilevered from the rest ofvalve frame 8010, these portions of the commissure posts can be givenany desired degree of flexibility or stiffness independent of thestiffness or flexibility designed into other parts of the valve frame.

Note that the prosthetic valve is preferably built up (constructed) fromcomponents that are initially separate as follows: (1) frame 8010, (2)sheet material 8300, and (3) leaflets 500. Further note that the orderof assembly is typically as follows: (1) frame 8010 is provided, (2)sheet material 8300 is added to frame 8010, and (3) leaflets 500 areadded inside the assembly of elements 8010 and 8300. Amplifying thislast point somewhat, the three leaflets 500 may be stitched togetherside-edge-to-side-edge prior to immediately above-mentioned step (3).Then above-mentioned step (3) may include (a) dropping the assembly ofleaflets into place inside annular structure 8200/8300, (b) suturing theleaflets individually to each commissure post 8264 (e.g., at locations540), and (c) suturing the belly of each leaflet to sheet material 8300(e.g., at locations 550) to form the actual valve. Those skilled in theart will appreciate that variations on this are possible. In general,however, it is typically the case that no valve exists separate fromframe structure 8010, or prior to addition of elements 8300 and 500 toframe structure 8010.

Again, it is expressly stated that FIGS. 28-32 and the immediately aboveparagraphs refer to frame embodiment 8010 only as an example, and thatthese principles are equally applicable to other embodiments shown anddescribed elsewhere in this specification.

To quantify what is meant by valves of this invention being collapsibleand re-expandable, it is preferred that a diameter of a valve inaccordance with this invention be collapsible by at least about 50%(e.g., from about 20-30 mm when fully expanded to about 10-15 mm whenfully collapsed). All of the valves shown herein are capable ofcollapsing by amounts typified by what is said in the immediatelypreceding sentence. More preferably, the percentage of such diameterreduction when the valve is collapsed is in the range from about 60% toabout 80% (e.g., to about 5-10 mm for a 25 mm expanded valve). At leastthe valves shown in the FIGS. from FIG. 12 to the end are capable ofcollapsing by amounts typified by what is said in the immediatelypreceding sentence. Note that a 60% diameter reduction means that thediameter of the collapsed valve is 40% of the diameter of the expandedvalve. An 80% diameter reduction means that the diameter of thecollapsed valve is 20% of the diameter of the expanded valve.

From the foregoing it will be appreciated that the valves of thisinvention can be reduced in circumferential size (e.g., for lessinvasive delivery of the valve into a patient) and then re-expanded tofull (or normal) circumferential size at the valve-implant site in thepatient. The valves of this invention typically change circumference inthis way without otherwise radically changing in shape. Reduction incircumference may be accompanied by a temporary increase in length ofthe valve. Also, a skirt like 240, 1240, etc., that is resilientlybiased to deflect radially out may be temporarily deflected in. But thetubular or cylindrical outer periphery of the valve (e.g., structure 10,1010, 2010, 3010, or 4010) preferably always remains tubular orcylindrical. It preferably does not undergo any radical shape changesuch as would be involved if it were folded, creased, or wound along thelength (blood flow axis) of the valve. The circumference of the valve isreduced by compression of component 10, 1010, etc., in the annular orcircumferential direction, which leaves component 10, 1010, etc., a tubeof the same basic shape (although of different size) at all times. Thistype of reduction of the circumferential size of component 10, 1010,etc., (and therefore the remainder of the valve structure), and whichdoes not rely on folding of component 10, 1010, etc., along its lengthor winding of that component about a longitudinal axis, may be referredto herein as annular or circumferential collapsing, compression,shrinking, reduction, or the like.

In the above discussion it is said that ring 100, 1100, 2100, etc., isconnected to stent 200, 1200, 2200, etc., substantially solely by strutstructures 280, 1280, 2280, etc., that are adjacent to the commissureposts or tips 236, 1236, 2236, etc. A purpose of this is to leaverelatively large openings 140, 1140, 2140, etc. between annularlyadjacent pairs of the strut structures. To quantify what is meant by thephrase adjacent to the commissure posts in this context, it can be saidthat in any given valve, openings 140, 1140, 2140, etc. collectively(preferably) constitute about two-thirds (or an even larger fraction) ofthe distance in the annular direction around the valve at the height ofthe commissure tips when the valve is expanded. Thus, for example, inthe first-described embodiment, W1 (FIG. 3 ) is the width of onerepresentative opening 140 at the level of commissure tips 236. W2 isthe width of one representative strut structure 130, etc., at that samelevel. The sum of dimension W1 for all three openings 140 is at leasttwo-thirds the circumference of the fully expanded valve at the level ofthe commissure tips. The sum of dimension W2 for all three strutstructures is less than one-third that valve circumference. This meansthat the components of each strut structure are relatively close to theadjacent commissure post or tip.

It will be understood that the foregoing is only illustrative of theprinciples of this invention, and that various modifications can be madeby those skilled in the art without departing from the scope and spiritof the invention. For example, the number and shapes of the variouscells (like 110 and 210) in component 10 or the like can be differentfrom the number and shapes of the cells shown in the FIGS. herein.Similarly, the number of undulations in serpentine structures such as1160 a, 1160 b, 1162, or the like can be different from the numbersshown in the FIGS. herein.

1. A prosthetic heart valve, comprising: a collapsible and expandablestent assembly having first stent portion and a second stent portion,the first stent portion is coupled to the second stent portion to forman independent stent-in-stent design, the first stent portion and thesecond stent portion each being formed of nitinol so that each of thefirst stent portion and the second stent portion is self-expandable; aplurality of valve leaflets coupled directly to the second stent portionbut not directly to the first stent portion, the plurality of valveleaflets configured to allow blood to flow in a downstream direction,but to restrict blood from flowing in an upstream direction; a firstfabric at least partially covering an exterior surface of the firststent portion; and a plurality of projections formed on the first stentportion and extending in the upstream direction, the plurality ofprojections remaining uncovered by the first fabric so that theprojections are configured to engage tissue to prevent migration of theprosthetic heart valve in the upstream direction when the stent assemblyis in an expanded condition, wherein in the expanded condition of thestent assembly, the first stent portion has an expanded diameter that isgreater than an expanded diameter of the second stent portion.
 2. Theprosthetic heart valve of claim 1, wherein the projections are barbs. 3.The prosthetic heart valve of claim 1, wherein the first stent portionis coupled to the second stent portion via a plurality of individualattachment links that are positioned at spaced locations around acircumference of the stent component.
 4. The prosthetic heart valve ofclaim 3, wherein the first stent portion includes at least onecircumferential row of closed-perimeter cells.
 5. The prosthetic heartvalve of claim 4, wherein the closed-perimeter cells are diamond-shaped.6. The prosthetic heart valve of claim 5, wherein in the expandedcondition of the stent assembly, an inflow end of stent assembly flaresradially outwardly from a remainder of the stent assembly, the flareconfigured to help secure the stent assembly in place.
 7. The prostheticheart valve of claim 6, wherein a second fabric is coupled to the secondstent portion.
 8. The prosthetic heart valve of claim 7, wherein, in theexpanded condition of the stent assembly, the first stent portion isspaced from the second stent portion so that the plurality of valveleaflets cannot contact the first stent portion during operation of theprosthetic heart valve.
 9. The prosthetic heart valve of claim 8,wherein, in the expanded condition of the stent assembly, the firststent portion is substantially concentric with the second stent portion.10. The prosthetic heart valve of claim 9, wherein the second stentportion includes three commissure regions, the plurality of valveleaflets being coupled to the three commissure regions.
 11. Theprosthetic heart valve of claim 10, wherein, during operation of theprosthetic heart valve, the three commissure regions are spaced radiallyinwardly from the first stent portion so that a gap exists between anouter surface of the three commissure regions and an inner surface ofthe first stent portion.
 12. The prosthetic heart valve of claim 11,wherein the independent stent-in-stent design is configured to allow thethree commissure regions to flex independently of the first stentportion.
 13. The prosthetic heart valve of claim 12, wherein the firststent portion is configured to anchor the prosthetic heart valve withina heart so that the plurality of valve leaflets are positioned within anative valve annulus of the heart.
 14. The prosthetic heart valve ofclaim 13, wherein the prosthetic heart valve is devoid of structuresthat span directly between the first stent portion and the second stentportion in a manner that constrains independence of motion between thefirst stent portion and the second stent portion.
 15. The prostheticheart valve of claim 14, wherein, in an expanded condition of the stentassembly, the first stent portion is generally tubular or cylindrical.16. The prosthetic heart valve of claim 14, wherein the plurality ofindividual attachment links positioned a spaced distance below the threecommissure regions.